The levels of Cd, Pb, Cr, Ni, Cu, Co, Ba, Mn, Zn, Al and Fe were evaluated in indoor dusts from electronic workshops, cybercafés and offices in southern Nigeria. The study was aimed at providing ...information on the distribution patterns, and the associated risks that may arise from exposure of humans to these metals in indoor dusts from the three work environments. The dust samples were digested with aqua-regia and analyzed for the metal concentrations by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The metal concentrations (mg kg−1) in the indoor dusts from these work environments ranged from 0.2 to 20.5 Cd, 0.6–4810 Pb, 8.65–2210 Cr, 1.85–209 Ni, 6.75–2820 Cu, 0.25–19.6 Co, 22.7–597 Mn, 6.65–140 Ba, 43.3–7310 Zn, 1040–16,800 Al and 969–78,300 Fe. The metal distribution patterns in these dust samples followed the order: electronic workshops > cybercafés > offices. The concentrations of Cd, Pb and Cu in significant proportions of the dust samples from the electronic workshops and cybercafés surpassed their respective permissible limits in soils. The health risk assessment suggests considerable non-cancer risks arising from childhood contact with Pb in dust from the electronic workshops while no considerable non-cancer risk is associated with the adult and child exposure to dust from the cybercafés and offices. The results indicated that Cr and Pb are the main elements responsible for the non-carcinogenic risk arising from childhood exposure to electronic workshop dusts. The carcinogenic risk due to exposure of humans to metals in these dust samples were within the range regarded as safe by the USEPA.
•Considerable non-cancer risks for childhood contact with Pb in electronic workshop dusts.•Cr and Pb are the main elements responsible for the non-carcinogenic risk.•No considerable cancer risk from exposure of humans to dust-borne metals.
This study determined the background occurrence, distribution, and exposure risks of the sixteen priority polycyclic aromatic hydrocarbons (16-PAHs) in soils from the vicinity of petroleum tank farms ...in Western Delta, Nigeria. The samples were collected in the fifteen petroleum tank farms at 0-15 cm, 15-30 cm, and 30-45 cm depths. After extraction by ultrasonication with n-hexane/dichloromethane and clean-up in silica gel/alumina packed column. The concentration of PAHs was determined using gas chromatography fitted with mass spectrometry (GC-MS). The Σ16-PAHs ranged from 4.49 to 447.86 mg kg
-1
for all sites and depths. The concentration of the Σ16-PAHs in the samples exceeded the Department of Petroleum Resources (DPR) target values, and 38% depicts PAHs concentrations above the DPR intervention values, this suggests the presence of high molecular weight petroleum products such as diesel and heavy oil, and soils from the tank farms' are polluted with a considerable amount of soils within PAHs. The total cancer risk falls within the low to moderate category. The principal sources of PAHs are petrogenic and low-high-temperature combustion processes. This study provided empirical data on the pollution load, origin, and associated risks of PAHs in soils in some petroleum tank farms. Appropriate clean-up actions are needed to mitigate the accumulation of PAHs in soil and biota and the ecological and human exposure risks in the surrounding aquatic and terrestrial environments.
Supplemental data for this article is available online at online
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Contamination of vegetables with organochlorine pesticides (OCPs) during cultivation could affect their nutritional value and also results in adverse health effects to consumers. Thus, this study ...evaluates human exposure to OCPs in vegetables from major cities in south-south Nigeria. A total of eighty vegetables consisting of Vernonia amygdalina, Telfairia occidentalis, Desmodium intortum cv and Talinum triangulare obtained from four major cities (Warri, Benin, Yenagoa and Port-Harcourt) in south-south Nigeria were analysed for OCPs using a gas chromatograph coupled with a mass selective detector. The results showed that the mean concentration of ∑20 OCPs in the vegetables ranged from 11.6 to 37.7 ng g−1 fresh wt for Vernonia amygdalina, 2.48–37.0 ng g−1 fresh wt for Telfairia occidentalis, 7.63–54.2 ng g−1 fresh wt for Desmodium intortum cv and 27.3–57.3 ng g−1 fresh wt for Talinum triangulare. The concentrations of OCPs were generally lower than their respective Maximum Residue Limits (MRLs). The EDI values of the ∑20 OCPs in the vegetables ranged from 141 to 464 ng kg−1 bw day−1 for children and 26.5–87.0 ng kg−1 bw day−1 for adults. The EDI of ∑Drins, ∑Chlordanes and ∑DDTs for the vegetables were below their respective acceptable EDI values set by FAO/WHO Joint Meeting on Pesticide Residue. The hazard index values for children and adults were generally <1 suggesting that there is no potential non-carcinogenic risk for children and adults consuming the vegetables. The total cancer risk values were above 1 × 10−6 and indicated that children and adults have moderate and low carcinogenic risks respectively from ingestion of these vegetables. The isomeric ratios and principal component analysis result showed that OCPs in these vegetables originated from both historical and recent usage in vegetable cultivation.
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•The vegetables were contaminated with OCPs.•The OCPs in the vegetables were lower than their respective MRLs.•The daily intakes were below their respective FAO/WHO acceptable limits.•The TCR values indicated low to moderate carcinogenic risks.•OCPs in the vegetables originated from both historical and recent usage.
The characteristic concentrations of 28 PCB congeners, their spatial distributions, sources, and associated risks to the ecosystem were investigated in sediments of some rivers around a glass ...industry and power generating plant in the Niger Delta of Nigeria. Gas chromatography-mass spectrometry (GC-MS) was applied for the identification and quantification of PCBs in sediments from these rivers. The Ʃ28 PCB concentrations (dry weight) in sediments ranged from 1520 to 3540 ng g−1 for the Afiesere River, 976–5670 ng g−1 for the Edor River, and from 1440 to 6340 ng g−1 for the Okpare River. The homologue distribution patterns in sediments from these rivers indicated that low-chlorinated (2 Cl to 5 Cl) PCBs were more dominant than high-chlorinated (6 Cl to 10 Cl) PCBs with tri-, penta- and deca-PCBs as the top homologues. The PCB source analyses suggested that the PCB contamination of these river sediments could have originated from Aroclor mixtures, paints, pigments and other inadvertent sources. The risk assessment indicated a high risk to the ecosystem.
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•PCBs were determined in sediments from the Afiesere, Edor and Okpare rivers.•Low-chlorinated PCBs were dominant in the sediments.•Exposure of the ecosystem to PCBs in these sediments poses a high risk.•Sources of PCBs in sediments include Aroclor mixtures, paints and pigments.
In this study, the concentrations of 28 polychlorinated biphenyl (PCB) congeners, including 12 dioxin-like PCBs and 7 indicator PCBs, were determined in sediments around oil production facilities in ...the Escravos River Basin of the Niger Delta in Nigeria. The aim was to describe the spatial patterns, sources, and ecosystem risks associated with exposure to PCBs in sediments of this river basin. Gas chromatography-mass spectrometry (GC–MS) was used to determine the concentrations of PCBs in the sediments. The Ʃ28 PCB concentrations in sediments from the Escravos River Basin ranged between 226 and 31,900 ng g−1 with a median concentration of 2300 ng g−1. The results indicated that sediments around crude oil production facilities, such as, wellheads, flow stations, and truck lines, had significantly higher levels of Ʃ28 PCBs (p < 0.05) than those collected near residential communities within the river basin. The median concentrations of PCB homologues in sediments from this river basin followed the sequence: hexaPCBs > penta-PCBs > tetra-PCBs > hepta-PCBs > tri-PCBs > di-PCBs > deca-PCBs > octa-PCBs > nona-PCBs. The risk assessment of PCBs in sediments from this river basin suggest very high potential risks for both organisms and humans.
•PCBs were measured in sediments from the Escravos River Basin.•Low chlorinated PCBs were dominant in the sediments.•Potential ecological risk exists for exposure of organisms to PCBs in sediments.•PCBs in the sediments are associated with inadvertent sources.
This study assessed the concentrations, sources, and risks of polycyclic aromatic hydrocarbons (PAHs) in sediments from the Rivers Niger, Ase and Forcados in the western Niger Delta. The ...concentrations of PAHs (in μg kg−1 dry weight), as determined by gas chromatography–mass spectrometry, in sediments from these rivers varied from 2400 to 19,000, 2930 to 16,100, and from 1620 to 19,800 for the Niger, Ase and Forcados Rivers respectively. High molecular weight (HMW) PAHs were the most prevalent compounds present in these sediments. An assessment of the possible ecological and human health risks suggested high risks for both organisms and humans. The PAH source analysis suggested that sediments from these river systems were contaminated with PAHs arising from burning of biomass, gasoline/diesel emissions, burning of natural gas, and oil spillages.
•Sediments from the Niger, Ase and Forcados Rivers were contaminated with PAHs.•The PAH composition in these sediments showed prominence of 5- and 6-ring PAHs.•There is a high risk to both organisms and humans from these PAHs in sediments.•Remedial actions and stringent control measures are required to reduce this risk.•Possible sources of this PAH contamination have been identified.
Chlorinated organic compounds, such as polychlorinated biphenyls (PCBs), are a threat to both humans and the environment because of their toxicity, persistence, and capacity for long-range ...atmospheric transport. The concentrations of 28 PCB congeners, including 12 dioxin-like and seven indicator PCBs, were investigated in soils, and indoor and outdoor dusts from Port Harcourt city, Nigeria, in order to evaluate the characteristic distribution patterns in these media, their sources, and possible risk. The PCB concentrations varied from 4.59 to 116 ng g−1 for soils, and from 1.80 to 23.0 ng g−1 and 2.73 to 57.4 ng g−1 for indoor and outdoor dusts respectively. The sequence of PCB concentrations in these matrices was soil > outdoor dust > indoor dust. The composition of PCBs in these matrices indicated the prevalence of lower chlorinated PCBs in indoor and outdoor dusts, while the higher chlorinated congeners were dominant in soils. Di-PCBs were the predominant homologues in indoor dusts, while deca-PCBs were the most prevalent homologues in outdoor dusts and soils. The TEQ values of dioxin-like PCBs in 60 % of the soils, 100 % of the indoor dust, and 30 % of the outdoor dust were above the indicative value of 4 pg TEQ g−1 established by the Canadian authority. The hazard index (HI) values for exposure of adults and children to PCBs in these media were mostly greater than one, while the total cancer risk (TCR) values exceeded the acceptable risk value of 10−6, which indicate probable non-carcinogenic and carcinogenic risks resulting from exposure to PCBs in these media. Source analysis for PCBs in these matrices shows that they originated from diverse sources.
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•PCB-contaminated dusts and soils from Port Harcourt city were investigated.•PCB concentrations in soils were higher than those of outdoor and indoor dusts.•Tri-, penta-, and deca-PCBs were the dominant homologues in these matrices.•Exposure to PCBs in these matrices poses a risk to the ecosystem and humans.•PCBs in these matrices originated from diverse sources.
In this study, some physicochemical properties, concentrations of metals (Pb, Cd, Cu, Zn, Fe, and Mn), and the overall water quality from Bomadi Creek in the Niger Delta of Nigeria were assessed over ...two seasons. Water samples were collected from designated areas along the course of the river and were prepared for analysis by standard procedures. The ranges of the mean values for some water quality indicators were found to be as follows: pH: 7.40–8.17, turbidity (NTU): 20.5–42.3, total dissolved solids (mg L
−1
): 27.5–44.7, total suspended solids (mg L
−1
): 34.1–61.7, dissolved oxygen (mg L
−1
): 3.07–6.53, biochemical oxygen demand (mg L
−1
): 0.13–2.77, total hardness (mg L
−1
): 28.3–60.0, and nitrate (mg L
−1
): 0.37–0.92. Only the turbidity values exceeded the permissible limit of 5 NTU. The concentration ranges (mg L
−1
) for the six metal ions determined were: Pb: 0.01–0.02, Cd: 0.01–0.03, Zn: 0.1–0.3, Cu: 0.03–0.07, Fe: 0.6–0.9, and Mn: 0.01–0.05. There were no significant variations in many of the locations between the wet and dry seasons. The comprehensive pollution index values indicated severe pollution of the Creek, with Cd, Fe, and turbidity, identified as the major contributors to the deteriorated water quality. The sources of high loads of Cd, Fe, and turbidity in this river system include discharges from oil production activities, speed boats, illegal bunkering, and domestic waste dumps. Principal component and cluster analysis were used to establish relationships between the various parameters and sites. The risk assessment indicated adverse non-carcinogenic and carcinogenic risks arising from human consumption of the water. The risk is higher for children than adults. Therefore, the Bomadi water is considered unsuitable for drinking and other domestic purposes, and remediation is required.
Polycyclic aromatic hydrocarbons (PAHs) are a group of semi-volatile and persistent organic compounds considered priority pollutants because of their pervasive nature and high toxicity to the ...ecosystem and humans. Therefore, this study aimed to evaluate the PAH concentrations in dust and soils around informal trade sites (ITS) in Nigeria to determine the level of risk, sources, and significance of these activities to the PAH load of the environment. The 16 US EPA PAHs in dust and soils from ITS were determined by gas chromatography-mass spectrometry (GC-MS). The PAH concentrations in dust from these informal trade sites varied from 120 to 8790, 56 to 4780, and 102–1090 μg kg−1 for automobile mechanic workshops (AMW), car dismantling (CDS), and material recovery sites (MRS), respectively, whereas those of soils ranged from 3000 to 95,500, 554 to 14,700, and 966–25,200 μg kg−1 for AMW, CDS, and MRS respectively. The PAH profiles indicated that 3- to 5-ring PAHs were prominent in dust and soils around the ITS. The concentrations of the US EPA 16 PAHs in dust and soils from these ITS showed no correlation with organic matter, while the concentrations of PAH homologues in soils of these ITS showed no correlation with those of dust. Incremental lifetime cancer risk (ILCR) values in the magnitude of 10−4 to 101 were obtained for adult and childhood exposure to PAHs in dust and soils from these ITS. Exposure to PAHs in dust from these ITS gives rise to less risk than for soils. The results indicated that automobile mechanic workshops contribute more PAHs to the environment than car dismantling and material recovery activities. The source analysis showed that the PAH contamination of these sites arises from burning of biomass, plastic materials, and oils, and emissions from vehicles.
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•Dust and soils around informal trade sites (ITS) are contaminated with PAHs.•Activities of these ITS are potent contributors of PAHs to the environment.•3- to 5-ring PAHs were the dominant species in soils and dust from the ITS.•PAHs in these matrices are of potential risk to the ecosystem and human health.•PAH profiles in these matrices reflect dominance of pyrogenic sources.
This study evaluated the occurrence characteristics to trace the origin and associated risks of organochlorine pesticides (OCPs) in soils from urban, suburban, and rural stormwater reservoirs. ...Samples were collected from the topsoil (0-15 cm) and subsoil (15-30 cm), and quantified for Ʃ
20
OCPs using a gas chromatography-mass spectrometry (GC-MS) after extraction with n-hexane and dichloromethane. The concentrations of ∑
20
OCPs ranged from 29.3 to 77.9 ng g
−1
. The average concentration of Σ
20
OCPs in the catchments and the isomer compositional pattern is in the order of urban > sub-urban > rural and ∑HCHs > ∑Chlordane > ∑Drins > ∑Endosulfan > ∑DDTs respectively. The HI levels for infants' exposure were seven-fold that of adults' exposure and were > 1. The human exposure risk is in the order of RiskIng > RiskDerm > RiskInh. The RiskIng and RiskDerm in infants' exposure were higher than in adults' exposure, while the RiskInh in adult exposure was higher than that of infants' exposure. The total cancer risk was higher than the acceptable total cancer risk value. The ecological risk indicated a significant biological effect in 56% of the samples. The source apportionment showed that Ʃ
20
OCPs were of historical and fresh inputs from the non-point and direct origin. Standard clean-up and source-directed mitigation actions should be carried out to assuage the associated risks.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
